Harmonic Balancers

I was running a professional products SFI balancer on my 410.. slipped the ring and timing wasn't accurate, but it didn't separate. I then swapped to the cheaper version for car show season, made a couple runs at the track and it separated completely. After that I purchased an ATI damper, the ATI depending on the version you get is not stock width and pulleys will need to be adjusted for fitment.
The new 408 has a Trickflow Trackmax SFI balancer, this engine is new so I don't have any good or bad to say about it yet, but it does align properly with stock pulleys.